San Francisco TowerSan Francisco, California, US
Twisted Tower San Francisco
This 120 story tower concept for the transbay terminal site was done as an exploration of a structural system that could provide an architectural response to the issues of vortex drag found at the corners of monolithic towers. The 60 degree rotation provides for a relatively direct forming system from one floor to another and the negative visual aspects of a greater rotation are avoided. In addition the shingled panels of unitized curtainwall provides a simplified construction using flat panels and the overall shape allows for diagonal bracing to remain outboard of the enclosure system as it engages the primary structural frame at tangent points.